Corrosion of Fe-9Cr Steels in Sodium Fast Reactors Environments

The sodium cooled fast reactor is selected by France as the most mature GEN IV concept to be industrially developed by the year 2040. A collaborative research program has been established together with EDF and Areva NP. In this program, different innovations are being considered in the design of the reactor leading to the use of various environments apart from liquid sodium and water vapor encountered in the “classical” sodium fast reactors. As a matter of fact, considerations on the suppression of the water-sodium reaction risk led to the proposal of the use of alternative coolants such as Pb-Bi involving an intermediate circuit between the primary sodium and the steam generator. Other concepts involve the use of supercritical CO2 instead of water vapor in the energy conversion system. In all cases, structural materials encounter severe conditions regarding corrosion concerns: high temperatures and possibly aggressive chemical environments. In this paper, status of the research performed in CEA on the corrosion behavior of the structural material and especially Fe-9Cr steels is presented in the various environments: sodium (see paper by JL Courouau), Pb-Bi, water vapor and CO2. The materials studied are metallic materials: austenitic and ferrito-martensitic steels as well as ODS steels as an option for the cladding material. In the different environments studied, the scientific approach is identical, the objective being in all cases the understanding of the corrosion processes to establish recommendations on the chemistry control of the coolant and to predict the long term behavior of the materials by the development of corrosion models. First, the corrosion mechanisms are analyzed using dedicated experimental devices. As a matter of fact, the complex environments require also controlled, safe and precise experimental systems to perform long duration corrosion tests (several thousands of hours). Therefore, specific experiments, adapted to each corrosive medium, are carried out in the laboratory. For example: - laboratory scale loops are used for liquid metals corrosion studies (use of rotating cylinders to simulate high turbulent conditions), - thermogravimetric analyses are also used to perform gas corrosion studies in representative temperature and environmental conditions,… Then, multi-scale characterization of the materials studied is performed (FEG-SEM, EDX, XRD, GD-OES…), together with precise analyses of the environments tested (in situ measurements with specific probes, gas chromatography…). Corrosion mechanisms are then proposed and models developed, depending on the advancement and the maturity of the program

Calibration procedures of the Tore-Supra infrared endoscopes

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Spatial analysis of black spruce ( Picea mariana (Mill.) B.S.P.) radial growth response to climate in northern Québec – Labrador Peninsula, Canada

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Epidemiology, risk factors and clinical course of SARS-CoV-2 infected patients in a Swiss university hospital: An observational retrospective study.

This study aims to describe the epidemiology of COVID-19 patients in a Swiss university hospital. This retrospective observational study included all adult patients hospitalized with a laboratory confirmed SARS-CoV-2 infection from March 1 to March 25, 2020. We extracted data from electronic health records. The primary outcome was the need to mechanical ventilation at day 14. We used multivariate logistic regression to identify risk factors for mechanical ventilation. Follow-up was of at least 14 days. 145 patients were included in the multivariate model, of whom 36 (24.8%) needed mechanical ventilation at 14 days. The median time from symptoms onset to mechanical ventilation was 9·5 days (IQR 7.00, 12.75). Multivariable regression showed increased odds of mechanical ventilation with age (OR 1.09 per year, 95% CI 1.03-1.16, p = 0.002), in males (OR 6.99, 95% CI 1.68-29.03, p = 0.007), in patients who presented with a qSOFA score ≥2 (OR 7.24, 95% CI 1.64-32.03, p = 0.009), with bilateral infiltrate (OR 18.92, 3.94-98.23, p<0.001) or with a CRP of 40 mg/l or greater (OR 5.44, 1.18-25.25; p = 0.030) on admission. Patients with more than seven days of symptoms on admission had decreased odds of mechanical ventilation (0.087, 95% CI 0.02-0.38, p = 0.001). This study gives some insight in the epidemiology and clinical course of patients admitted in a European tertiary hospital with SARS-CoV-2 infection. Age, male sex, high qSOFA score, CRP of 40 mg/l or greater and a bilateral radiological infiltrate could help clinicians identify patients at high risk for mechanical ventilation

Concept and development of ITER divertor thermography diagnostic

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